In fact, at first I wondered if Wickett's Remedy was actually non-fiction because the notes reminded me of academic writing, with so many important bits at the bottoms of pages and hidden in appendices. But the notes are not scholarly at all. Though there is something distanced about them, that's true: about a quarter of the way into the novel, I understood why. Once you realize what it's all about, it's not gimicky; it makes sense in the context of the story.
In many ways, Myla Goldberg's second novel is a story about distance, about the spaces between. Not only structurally (the spaces between the marginalia and the narrative text itself), but thematically. (If you're interested, there is a longer discussion of the distances in the novel here.)
Through Lydia's tale, readers are brought to ask questions that are still relevant today, the biggest question being "Doesn't it mean something?" The history books would have little to say about stories like Lydia's; the stories of ordinary families often fall into those spaces between and are left untold because they don't mean much. It's reassuring to catch a glimpse of them in Wickett's Remedy, reassuring to know that writers like Myla Goldberg are concerned with matters of meaning.